Reaction participants Show >> << Hide
- Name help_outline cytosine Identifier CHEBI:16040 (Beilstein: 2637; CAS: 71-30-7) help_outline Charge 0 Formula C4H5N3O InChIKeyhelp_outline OPTASPLRGRRNAP-UHFFFAOYSA-N SMILEShelp_outline Nc1cc[nH]c(=O)n1 2D coordinates Mol file for the small molecule Search links Involved in 8 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:29935 | RHEA:29936 | RHEA:29937 | RHEA:29938 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Characterization of the Escherichia coli codBA operon encoding cytosine permease and cytosine deaminase.
Danielsen S., Kilstrup M., Barilla K., Jochimsen B., Neuhard J.
The nucleotide sequence of a 3.1 kb segment carrying the cytosine deaminase gene (codA) from Escherichia coli was determined. The sequence revealed the presence of two open reading frames, the first (codB) specifying a highly hydrophobic polypeptide and the second specifying cytosine deaminase. A ... >> More
The nucleotide sequence of a 3.1 kb segment carrying the cytosine deaminase gene (codA) from Escherichia coli was determined. The sequence revealed the presence of two open reading frames, the first (codB) specifying a highly hydrophobic polypeptide and the second specifying cytosine deaminase. A two-codon overlap between the two reading frames indicates that they constitute an operon. Transcription of the operon was found to be regulated by exogenous purines. Polypeptides specified by each of the two reading frames were expressed in minicells, and the codB gene product was found to be highly enriched in the membrane fraction. Uptake experiments showed that the CodB protein is required for cytosine transport into the cell and that the intracellular accumulation of cytosine correlated with the codB gene dose. A topological model for the cytosine permease in the cytoplasmic membrane is proposed. << Less
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Characterization of the Saccharomyces cerevisiae cytosine transporter using energizable plasma membrane vesicles.
Pinson B., Napias C., Chevallier J., Van den Broek P.J., Brethes D.
The purine-cytosine permease is a carrier localized in the plasma membrane of the yeast Saccharomyces cerevisiae. The energetics of cytosine transport catalyzed by this permease has been studied in an artificial system obtained by fusion between proteoliposomes containing beef heart cytochrome c o ... >> More
The purine-cytosine permease is a carrier localized in the plasma membrane of the yeast Saccharomyces cerevisiae. The energetics of cytosine transport catalyzed by this permease has been studied in an artificial system obtained by fusion between proteoliposomes containing beef heart cytochrome c oxidase and plasma membrane-enriched fractions of a S. cerevisiae strain overexpressing the permease. Upon addition of an energy donor, a proton-motive force (inside alkaline and negative) is created in this system and promotes cytosine accumulation. By using different phospholipids, it is shown that cytosine uptake is dependent on the phospholipids surrounding the carrier. It was demonstrated that the purine-cytosine permease is able to catalyze a secondary active transport of cytosine. By using nigericin and valinomycin, the DeltapH component of the proton-motive force is shown to be the only force driving nucleobase accumulation. Moreover, transport measurements done at two pH values have shown that alkalinization of intravesicular pH leads to a significant increase in cytosine uptake rate. Finally, no specific role of K+ ions on cytosine transport could be demonstrated in this system. << Less